Chair-iron.



H. G. HUNN.

CHAIR IRON. APPLIOATION FILED MAR.19,1912.

Patented Nov. 19, 1912.

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HOWARD Gr. HUNN, 0F NEW YGRK, N. Y.

CHAIR-IRON.

Speccation of Letters Patent. Application filed March 19, 1912.

Patented Nov. 19, 1912. serial no. 684,706.

To all whom it may concern:

Be it known that I, HOWARD G. HUNN, a citizen of the, United States of America, residing at New York city, in the county and State of New York, have invented certain new and useful Improvements in Chair- Irons, of which the following is a specification.

My invention relates to chair irons generally, and is more especially applicable for use in connection with the type of chairs generally termed stenographers chairs.

The principal object of my present invention is to provide simplified and improved means whereby the back rest in such chairs may be easily and quickly adjusted, both vertically and toward and away from the seat, and firmly retained in such adjusted position.

@ther objects of the invention, and its advantages and detail construction will more fully appear from the following' specification, reference being had to the accompanying drawings, wherein- Figure 1 is a top plan view of the improved chair iron, the member for supporting the back being shown in section; and Fig. 2 is a central vertical section of the chair iron shown in connection with a part of a chair, certain of the elements appearing in elevation.

Referring to the drawings by reference characters, 10 denotes a suitable hub, usually of iron, provided with sockets to removably receive the legs 1l of the chair. The hub is formed with an upper integral plate 12, and between the plate l2 and a lower removable plate 13 the legs 1l are secured by means of screws 111 or the like, passing through the lower plate and into the legs. The hub is longitudinally, centrally, bored and revoluble in said bore is a spindle or rod 15 which is held against vertical movement by a cotter pin 16 passing through the spindle near the lower end thereof, and a set collar 17 arranged adjacent the plate 12 and adapted to be held to the spindle by a set screw 18.

The mechanism so far described is of the ordinary or usual construction, and forms no part of my invention except as such mechanism or parts thereof enter into combination with the invention.

To 'enable the following description of the details of my invention-'liebe'clearly understood, it is to be noted that in chairs of the type to which the device is part-icularly applicable, the seat portion of the chair is vertically adjust-able but is not adapted to be tilted from its horizontal plane, whereas the back of the chair carrying the back rest is adjustable vertically as well as toward and away from the seat and may also be tilted against spring tension, and automatically returned to its initial adjusted position after cessation of the force producing the tilting effect.

Arranged to slide longitudinally on the spindle 15 is a split sleeve 19 provided with lugs or ears 2O through which passes the partially threaded stem 21, having the head 22 at one end, the opposite, threaded, part of the stem being engaged by the internally threaded sleeve 23 provided with the hand wheel or operating member 24. The construction just described is such that by turning the hand wheel 2-1- in one direction the parts of the sleeve 19 are permitted to separate thus enabling the sleeve to be moved along the spindle, and when the wheel is turned in the oppositie direction the sleeve is clamped down against the spindle 15.

Preferably formed integrally with the sleeve 19 near its upper terminus is a supporting plate formed with the depending lateral walls 26. This plate serves to lixedly support the arms designated generally as 27 to which the seat 28 is secured. The general configuration of the arms 27 is substantially lll-shaped, and each arm is formed of two integral metal webs 27ab and 27b at right angles to each other (Fig. 2). lntermediate the ends, the arms 27 are attached to the plate 25, the web 27'L1 lying on the upper face of said plate and the web 27b lying against the wall 26. The arms are attached firmly to the supporting plate by the bolts or rivets 29 and 30, the latter being larger than the bolt 29, for a purpose to be presently explained. In addition to securing the arms 27 to the plate 25, the bolt 30 also serves as a pivot for the back supporting means preferably formed as a pair of arms or bent plates 31, which as best seen in Fig. l, are parallel and spaced apart a portion of their length, then curve toward each other at the portions 31u, and finally are brought into the position where they may conta-ct, as at 31", near their outer extremities. The arms or plates are so formed thatl for a portion of their length they eX- tend parallel to the intermediate web sections 27 and then extend under the rear ends of the arms 27 (Figs. 1 and 2). At the ends opposite the parts 31b the arms 30 are of angular formation and constitute uprights 31c each provided with a substantially triangular notch 32, directed toward the rear end of the chair iron. The purpose and function of these notches will be fully hereinafter explained.

The parts 31b of the arms 31 are provided with alining orifices through which passes a threaded stem 33, having a head 34 at one end and its opposite end engaged by an internally threaded sleeve 35 provided with an operating wheel 36. Mounted on the stem 33 adjacent the parts 31b is a pair of centrally orificed collars or rings 37, the outer faces, 'z'. e. those farthest away from the parts 31, being cut with teeth of suitable pitch. Placed on the stem 33 adjacent the collars 37 is a pair of centrally oriiiced annular clamp arms 38, the inner faces of which are toothed to mesh with the teeth on the collars 37, and the outer extremities of which arms 38 are formed as jaws 39, the clamping faces of which are preferably angular in form. the angle being somewhat less than a right angle. These clamp jaws serve to adjustably retain the dovetailed portion 40 of a bar or plate 41 which is adapted to be secured by screws 42 or the like to the tiltable back 43 of the chair, carrying the back rest proper 44.

From the description just given it will be apparent that by loosening the clamp jaws they may be revolved about the stud 33 to obtain the desired adjustment of the back 43 toward or away from the seat 28, and by moving the back 43 with its attached plate 40-41 up or down the desired vertical adjustment may be secured, and after the back has been suitably adjusted the hand wheel 36 is revolved in the proper direction wherebythe teeth of the clamp arms 38 engage the teeth of the collars 37 and the jaws 39 firmly retain the portion 40 of the bar 41.

Projecting upwardly from, and resting upon, the plate 25 is a bracket 45, the upper portion of which is shaped as a collar or boss 46 'positioned intermediate the uprights 31c of the arms 31. Guided loosely in the boss 46 is a stem or rod 47 having one end threaded as at 48 and adapted to receive a stop collar 49 and an internally threaded sleeve 50 provided with the operating part 51. The stem 47 is encircled by a coiled extension spring 52, one end oi' which engages the boss 46 and the other end of which abuts against the stop collar 49. At its end opposite the portion 48, the stem 47 is formed with an enlarged head 53 which is passed through a pivotal resistance plate 54, the arms 55 of which are provided with the wedge shaped projections 56, adapted to enter and having rocking movement in the notches 32 formed in the uprights 31C. By appropriate movement of the sleeve 50 the tension of the spring 52 may be regulated to the desired degree, movement of the sleeve 5() from left to right forcing the collar 49 inward and compressing the spring, and movement in the opposite direction permitting the spring to unfleX to a degree corresponding to the number of turns given sleeve 50.

I will now proceed to describe how a chair iron is assembled and the manner in which the same operates.

After the hub and legs have been set up and thespindle 15 positioned in the hub, the

split sleeve is put in position on the spin-v dle. rfhe split sleeve. carries the plate 25 and the pairs of arms 27 and 31 so that by positioning the sleeve the supporting arms of the seat and the back are, at the same time, properly placed. Then the bracket 45 is placed on the plate 25, the resistance plate 54 is placed with its wedge edges 56 in the notches 32, the stem 47 inserted through the openings in plate 54 and the boss 46, the spring placed about the stem and the stop collar 49 and sleeve 48 screwed down on the stem until the desired tension of the. spring has been reached. Thereafter the plate 41, which has been attached to the back 43, is placed with its dovetail part 40 in the clamp jaws, the latter are swung about the pivot 33 until the desired adjustment has been obtained, and then by one movement, viziscrewing down the hand wheel 36, the clamp jaws are brought tightly against the part 40 and the clamp arm teeth tightly mesh with the teeth on the collars 37, and the parts are fixed in adjusted position. If now the chair be occupied, and the occupant lean against the back rest 44, the back 43 is tilted away from the seat 28, the spring 52 is compressed in a perfectly straight line, no torsional strain of any kind being produced. vWhen the back 43 is relieved of pressure the spring 52 extends and returns the back 43 to its initial adjusted position.

Having described my invention, what I claim as new and desire to secure by Letters Patent is l. A device of the character described, embodying therein a back rest supporting member, a pair of revolubly mounted clamp jaws each thereof provided with a toothed face, said jaws having means for releasably engaging said back supporting member, a pair of revolubly mounted collars interposed between said jaws, each of said collars having one of its faces provided with teeth to engage the teeth on one of said jaws, and

means for locking said jaws and collars together in adjusted position.

2. A device of the character described, embodying therein a back rest supporting member, a1 pair'of'revolubly mounted clamp' jaws each thereof consisting of a substantially annular member having teeth on its inner face and an extended undercut member adapted to engage said back rest supporting member, a pair of revolubly mounted collars interposed between the annular members of the clamp jaws, each of said collars having a toothed face to engage the teeth on one of said clamp jaws, and means for locking said jaws and collars together 1o in adjusted position.

In testimony whereof I have aflxed my signature in presence of tWo Witnesses.

HOWARD G. HUN N Vit-nesses:

` CLARISSA FRANCK, HELENE. KORTH.

Copies of this patent may be obtained for ve cents each, by addressing' the Commissioner of Patents, Washington, D. C. 

